Crops: The Lynch File: Headline - snake oil or the greatest fungicide for corn?

Sunday, August 10, 2008

Is Headline the greatest thing since Pursuit or Accent or Roundup?
Maybe not, but it could be the start of getting to the next yield plateau in corn production

by PAT LYNCH

In the last 35 years, we've have seen a lot of chemicals change the way we grow crops. In the early 1970s, we went away from 2,4-D and atrazine post-emergent herbicides on corn to pre-emerge and ppi herbicides. Corn yields went up. Based on what we know today, yields went up because farmers controlled weeds before they saw them.

The introduction of Roundup greatly increased yields by killing perennial weeds before the crop was planted. In the early 1990s, Accent and Ultim, sprayed to control quackgrass, allowed crop rotation since there was no carry over of atrazine. Also in the '90s, Pursuit post-emergent introduced a whole new way to grow soybeans.

A few years ago, spraying fungicides on wheat increased yields. I believe that fungicides on corn will be the introduction of a new way of getting more yield from a corn acre.

One of the products leading this wave is Headline. It has received a lot of media exposure and has been hailed as the greatest fungicide for today's corn acre. Others are accusing Headline of being the biggest snake oil product ever. There has been a lot of research done on Headline to try and figure out what is going on.

Interest first started with Headline when growers started to notice "different" things about crops sprayed with Headline – not every time but frequently enough to attract attention. There were part-fields sprayed with Headline before a hailstorm. To the line where the Headline was sprayed, the crop was better. There were fields sprayed with Headline after a hailstorm and again the sprayed part yielded better.

(There is reason to believe that a field which had suffered a hailstorm would yield better if treated with a fungicide. Hailstones inflict a lot of damage by bruising and breaking leaf tissue. This tissue is open to all the disease organisms in the air. Fungicides should help protect these open cuts.)

There are reports of fields sprayed with Headline looking better during a drought. It may be that, somehow, Headline helps to keep the water-conducting tissue (xylem) more healthy.

The research to date has found some things which appear to be occurring. Plants sprayed with Headline have reduced respiration. During the daytime, crops produce carbohydrates by photosynthesis. At night, plants respire. This uses carbohydrates. If you can reduce the amount of respiration, the total amount of carbohydrates in the plants is increased.

There has been research indicating that plants sprayed with Headline have increased nitrogen and carbon uptake. This should lead to increased yield.

There has been greenhouse research showing that plants treated with Headline, watered, and then put under moisture stress, handle this stress better than plants not sprayed with Headline. This effect seems to be more pronounced on grasses than on broadleaf plants.

Is Headline the greatest thing since Pursuit or Accent or Roundup? Maybe not, but I believe it is the start of getting to the next yield plateau in corn production.

Do the other registered fungicides have some of the same properties? Maybe. But I do believe I have seen enough information, research and on-farm comparisons involving Headline that every grower who wants to increase corn yields should be trying some on their farm. BF

Pat Lynch, CCA (ON), is head agronomist for Cargill in Ontario.